Optical line terminal channel terminal protection method, system, device and storage medium

Abstract

The application relates to an optical line terminal channel terminal protection method, system, device and storage medium, and relates to the technical field of communication. The method is applied to a wavelength division multiplexing passive optical network system. When a tunable protection optical line terminal channel terminal is in an initial state or a protection state, if an inter-channel-terminal protocol activation message sent by any optical line terminal channel terminal is received, the tunable protection optical line terminal channel terminal enters a pre-working state; in the pre-working state, the working wavelength of a transceiver of the tunable protection optical line terminal channel terminal is tuned according to a wavelength channel corresponding to the tunable protection optical line terminal channel terminal; a transmitter is turned on and downlink signals are transmitted, an optical network unit corresponding to a working optical line terminal channel terminal is confirmed to receive the downlink signals, and connection is established. The method realizes a one-to-many channel terminal protection switching mechanism through the tunable protection optical line terminal channel terminal and based on an ICTP activation message, and solves the problem that an original protection method cannot realize one-to-many protection of an OLT CT.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a method, system, communication device, and computer-readable storage medium for protecting optical line terminal channel terminals. Background Technology

[0002] The high-speed passive optical network (PON) technology widely deployed in existing networks mainly adopts time-division multiplexing EPON (Ethernet Passive Optical Network) or GPON (Gigabit Passive Optical Network) systems, where uplink and downlink operate on a single wavelength and transmit data through a mechanism that allocates their respective transmission times. WDM-PON (Wavelength Division Multiplexing Passive Optical Network), on the other hand, uses wavelength division multiplexing technology. The PON port of the central office OLT (Optical Line Terminal) equipment and the user-side ONU (Optical Network Unit) equipment each have a dedicated pair of wavelength channels, allowing for several times the number of users compared to traditional time-division PON. It primarily provides network connectivity for government and enterprise customers, wireless bearers, etc., especially in the 5G fronthaul field, where using WDM-PON can save backbone fiber resources and reduce network installation, maintenance, and operation costs and complexity.

[0003] In WDM-PON, the Optical Distribution Network (ODN) adopts a point-to-multipoint network structure, composed of passive components such as single-mode fiber and wavelength routing equipment, to achieve wavelength-based point-to-point transmission between the backbone and branch fibers. The WDM-PON system provides corresponding fixed operating wavelengths to the ONUs connected to each branch fiber end through the wavelength routing equipment in the ODN. This wavelength is determined by the physical connection and is fixedly allocated based on the WDM-PON uplink / downlink transmission wavelength allocation specifications.

[0004] Currently, the standardized Class B protection method for PON systems' OLT (Optical Line Terminal) CT (Channel Terminal) primarily involves one-to-one OLT CT protection for the working OLT via a backup OLT. Class B protection refers to a protection method that places no requirements on the ONU, with the OLT handling status detection and protection switching. Its main protection mechanism involves the OLT CT and its Class B protection counterpart OLT CT monitoring the uplink signal reception status of their respective wavelength channels and switching their roles (i.e., switching between active and backup roles) through ICTP (Inter-channel Termination protocol) message exchange, thereby performing protection switching for the working OLT CT.

[0005] One-to-one OLT CT protection increases equipment redundancy and wastes resources. Furthermore, due to the characteristics of WDM-PON, channels transmit based on different wavelength channels and are isolated from each other. The OLT CT cannot directly monitor the uplink signals of all wavelength channel pairs globally. Therefore, the original protection method cannot achieve one-to-many protection for the OLT CT, making the backup OLT lack a universal mechanism. Summary of the Invention

[0006] Based on this, it is necessary to provide a method, system, communication device, and computer-readable storage medium for protecting optical line terminals (OLTs) and channel terminals, which can adjust the protection of OLTs and channel terminals and implement a one-to-many channel terminal protection switching mechanism based on ICTP (Inter-Channel Terminal Protocol) activation messages.

[0007] In a first aspect, this application provides a method for protecting an optical line terminal (OLT) channel terminal. The method is applied to a wavelength division multiplexing (WDM) passive optical network system, which includes an adjustable protection OLT channel terminal and a working OLT channel terminal. The adjustable protection OLT channel terminal is used to protect the working OLT channel terminal within the same system. The method includes:

[0008] When the adjustable protection optical line terminal channel terminal is in the initial state or protection state, if it receives a channel terminal inter-channel terminal protocol activation message sent by any working optical line terminal channel terminal, it enters the pre-working state.

[0009] In the pre-operation state, the adjustable protection optical line terminal channel terminal tunes the operating wavelength of its transceiver according to the wavelength channel corresponding to the working optical line terminal channel terminal.

[0010] The adjustable protection optical line terminal (OLT) channel terminal turns on the transmitter and transmits downlink signals. The optical network unit corresponding to the working OLT channel terminal receives the downlink signals and establishes a connection.

[0011] In one embodiment, the method further includes:

[0012] When the adjustable protection optical line terminal channel terminal enters the initial state, the timer is activated;

[0013] If the timer expires, the adjustable protection optical line terminal channel terminal will enter the protection state.

[0014] In one embodiment, after the connection is established, the method further includes:

[0015] If the adjustable protection optical line terminal channel terminal in the pre-operation state receives an uplink transmission confirmation message, it enters the working state.

[0016] When in operation, if the adjustable protection optical line terminal channel terminal receives an upper-level management event from the element management system, it will enter a distress state.

[0017] In distress state, the adjustable protection optical line terminal (OLT) channel terminal sends an inter-channel terminal protocol activation message to the working OLT channel terminal in the initial state in an attempt to instruct the working OLT channel terminal to migrate from the initial state to the pre-working state.

[0018] In one embodiment, after sending an inter-channel terminal protocol activation message to a working optical line terminal (OLT) in its initial state, the method further includes:

[0019] The adjustable protection optical line terminal channel terminal responds to the fault description event and returns to the protection status.

[0020] In one embodiment, the method further includes:

[0021] If a working optical line terminal (OLT) channel terminal fails to receive an uplink signal within a set time period while in a signal loss state, it enters a distress state and periodically sends an inter-channel terminal protocol activation message to the adjustable protection OLT channel terminal.

[0022] In one embodiment, after periodically sending an inter-channel terminal protocol activation message to the adjustable protection optical line terminal (IPC) channel terminal, the method further includes:

[0023] The working optical line terminal channel terminal has entered a normal error state;

[0024] Normally, if a working optical line terminal (OLT) in an error state receives a reset message from the element management system, it will migrate back to the initial state.

[0025] In one embodiment, the method further includes:

[0026] If the working optical line terminal (OLT) in the initial state receives an inter-channel terminal protocol activation message sent by the adjustable protection OLT, it will transition to the pre-working state.

[0027] Secondly, this application also provides a wavelength division multiplexing passive optical network system, the system comprising an adjustable protection optical line terminal (IPC) channel terminal and a working optical line terminal (CRT) channel terminal, wherein the IPC channel terminal and the working optical line terminal are connected via an inter-channel terminal protocol communication connection; wherein:

[0028] The adjustable protection optical line terminal channel terminal is used to perform the following steps:

[0029] When the adjustable protection optical line terminal channel terminal is in the initial state or protection state, if it receives a channel terminal inter-channel terminal protocol activation message sent by any working optical line terminal channel terminal, it enters the pre-working state.

[0030] In the pre-operation state, the adjustable protection optical line terminal channel terminal tunes the operating wavelength of its transceiver according to the wavelength channel corresponding to the working optical line terminal channel terminal.

[0031] The adjustable protection optical line terminal channel terminal turns on the transmitter and transmits a downlink signal, confirms that the optical network unit corresponding to the working optical line terminal channel terminal has received the downlink signal, and establishes a connection.

[0032] The working optical line terminal (OLT) channel terminal is used to perform the following steps:

[0033] If a working optical line terminal (OLT) channel terminal fails to receive an uplink signal within a set time period while in a signal loss state, it enters a distress state and periodically sends an inter-channel terminal protocol activation message to the adjustable protection OLT channel terminal.

[0034] Thirdly, this application also provides a communication device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method described in the first aspect above.

[0035] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in the first aspect above.

[0036] The aforementioned optical line terminal (OLT) channel terminal protection method, system, communication equipment, and computer-readable storage medium, in a wavelength division multiplexing (WDM) passive optical network system, include an adjustable protection OLT channel terminal and a working OLT channel terminal. The adjustable protection OLT channel terminal is used to protect the working OLT channel terminals within the same system. When the adjustable protection OLT channel terminal is in its initial or protection state, if it receives an inter-channel terminal protocol activation message sent by any working OLT channel terminal, it enters a pre-working state. In the pre-working state, the adjustable protection OLT channel terminal tunes the operating wavelength of its transceiver according to the wavelength channel corresponding to the working OLT channel terminal. The adjustable protection OLT channel terminal turns on its transmitter and transmits a downlink signal, confirms that the optical network unit corresponding to the working OLT channel terminal has received the downlink signal, and establishes a connection. By employing the above method, an adjustable protection mechanism for optical line terminals and a one-to-many channel terminal protection switching mechanism based on ICTP activation messages is implemented. This solves the problem that the original protection method could not achieve one-to-many protection for OLT CTs, improves the versatility of the protection mechanism, reduces the complexity of the overall protection switching mechanism, and effectively reduces the overall cost of the WDM-PON system for application protection. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the WDM-PON system architecture configuration in one embodiment;

[0039] Figure 2 This is a schematic diagram of a traditional one-to-one protection architecture in one embodiment;

[0040] Figure 3 This is an application environment diagram of the optical line terminal channel terminal protection method in one embodiment;

[0041] Figure 4 This is a flowchart illustrating a method for protecting the channel terminal of an optical line terminal in one embodiment.

[0042] Figure 5 This is a schematic diagram of a Class B protection state machine of a conventional PON system in one embodiment;

[0043] Figure 6 This is a schematic diagram of an improved Class B protection state machine in one embodiment;

[0044] Figure 7 This is a flowchart illustrating the optical line terminal channel terminal protection method in another embodiment;

[0045] Figure 8 This is an internal structural diagram of a communication device in one embodiment. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0047] Understandably, referring to Figure 1 , Figure 1 This is a schematic diagram of the WDM-PON system architecture configuration in one embodiment. In WDM-PON, the optical distribution network (ODN) adopts a point-to-multipoint network structure, which is composed of passive devices such as single-mode optical fiber and wavelength routing equipment, to realize wavelength-based point-to-point transmission between the backbone and branch optical fibers.

[0048] Reference Figure 2 Currently, the standardized Class B protection method for OLT (Optical Line Terminal) CT (Channel Terminal) in PON systems primarily involves one-to-one OLT CT protection for the working OLT via a backup OLT. Class B protection refers to a protection method that places no requirements on the ONU, with the OLT handling status detection and protection switching. The Protection Wavelength Router (AN) and Wavelength Router (ODN) are the wavelength routing devices in the system. The main protection mechanism involves the OLT CT monitoring the uplink signal reception status of its respective wavelength channel and switching its role (i.e., switching between active and backup roles) through ICTP (Inter-channel Termination protocol) message exchange, thereby performing protection switching for the working OLT CT.

[0049] The inventors of this application have discovered that a one-to-one OLT CT protection method increases equipment redundancy and wastes resources. Furthermore, due to the characteristics of WDM-PON, channels transmit based on different wavelength channels and are isolated from each other. The OLT CT cannot directly perform global monitoring of the uplink signals of all wavelength channel pairs. Therefore, the original protection method cannot achieve one-to-many protection for the OLT CT, making the backup OLT lack a universal mechanism.

[0050] Based on this, this application provides a method, system, communication device, and computer-readable storage medium for protecting optical line terminals (OLTs). It can adjust the protection of OLTs and channel terminals and implement a one-to-many channel terminal protection switching mechanism based on ICTP activation messages, thus solving the problem that the original protection method cannot achieve one-to-many protection of OLTs and CTs.

[0051] The optical line terminal channel terminal protection method provided in this application embodiment can be applied to, for example, Figure 3 The application environment shown is as follows. In this WDM-PON system, multiple working OLT CTs are configured, namely OLT CT-1, OLT CT-2, ..., OLT CT-n in the working channel terminal group. A single wavelength-tunable backup OLT CT is used. Figure 3 The OLT CT-x in this document refers to the communication between the working OLT CT and the protection OLT CT via the Inter-Channel Terminal Protocol (ICTP) interface. Based on the ICTP messages sent by each working OLT CT, the protection OLT CT transitions between different states to protect each working OLT CT. It is understood that, for ease of understanding the embodiments provided in this application, some terms that may appear in the accompanying drawings and detailed descriptions are introduced below: CG refers to Channel Group; CP refers to Channel Pair; CT refers to Channel Termination; WR refers to Wavelength Router; AN refers to Access Node; ODN refers to Optical Distribution Network; Splitter refers to Optical Splitter; Backup tunable CT refers to Backup tunable CT.

[0052] In one exemplary embodiment, such as Figure 4 As shown, a method for protecting optical line terminals (OLTs) is provided. This method is applied to a wavelength division multiplexing (WDM) passive optical network system. The system includes an adjustable protection OLT and a working OLT. The adjustable protection OLT is used to protect the working OLT within the same system. The method includes:

[0053] Step 402: When the adjustable protection optical line terminal channel terminal is in the initial state or protection state, if it receives a channel terminal inter-terminal protocol activation message sent by any working optical line terminal channel terminal, it enters the pre-working state.

[0054] The adjustable protection optical line terminal (OLT CT) is a wavelength-tunable OLT CT, and its states include initial state, protection state, pre-operation state, operation state, and emergency state. The adjustable protection OLT CT communicates with the operational OLT CTs via the Inter-Channel Terminal Protocol (ICTP). The ICTP activation message (hereinafter referred to as the activation message) instructs the adjustable protection OLT CT to perform a state transition, taking over control of the corresponding wavelength channel as the activating role. The activation message can be represented as an ICTP:Active() message. The system containing the adjustable protection OLT CT includes one or more operational OLT CTs. When the adjustable protection OLT CT is in the initial or protection state, if it receives an ICTP:Active() message from any operational OLT CT via the ICTP interface, the adjustable protection OLT CT enters the pre-operation state.

[0055] Step 404: In the pre-operation state, the adjustable protection optical line terminal channel terminal tunes the operating wavelength of its transceiver according to the wavelength channel corresponding to the working optical line terminal channel terminal.

[0056] It is understandable that a wavelength division multiplexing passive optical network system may include multiple working optical line terminals and channel terminals. After the adjustable protection optical line terminal and channel terminal enter the pre-operation state, the working optical line terminal and channel terminal that sends the activation message will be the protected object.

[0057] In this process, the adjustable protection optical line terminal (APLT) channel terminal, which is in the pre-operation state, tunes the operating wavelength of its transceiver to match the wavelength channel of the working optical line terminal channel terminal that sends the activation message. This ensures that the operating wavelength of the APLT transceiver is within the wavelength channel range of the working optical line terminal channel terminal, allowing the APLT channel terminal to take over control of that wavelength channel and thus protect the working optical line terminal channel terminal.

[0058] Step 406: The adjustable protection optical line terminal channel terminal turns on the transmitter and transmits the downlink signal, confirms that the optical network unit corresponding to the working optical line terminal channel terminal has received the downlink signal, and establishes a connection.

[0059] The adjustable protection optical line terminal (OPCLT) channel terminal operates by transmitting and receiving signals based on a tuned operating wavelength, attempting to establish a connection with the corresponding optical network unit (ONU). Specifically, it attempts to establish a connection by transmitting downlink signals. If an uplink transmission acknowledgment message is received, it indicates that the connection has been successfully established, and the OPCLT channel terminal enters the working state. Optionally, if no transmission acknowledgment message is received within a certain period, it indicates that the connection has failed, which may indicate a failure of the optical fiber or optical transceiver.

[0060] In one alternative implementation, if connection establishment fails, the adjustable protection optical line terminal channel terminal will enter a normal error state.

[0061] The aforementioned optical line terminal (OLT) channel terminal protection method is applied to a wavelength division multiplexing (WDM) passive optical network (PON) system. The adjustable protection OLT channel terminal is used to protect the working OLT channel terminals within the same system. When the adjustable protection OLT channel terminal is in its initial or protection state, if it receives an inter-channel terminal protocol activation message from any working OLT channel terminal, it enters a pre-operation state. In the pre-operation state, the adjustable protection OLT channel terminal tunes its transceiver's operating wavelength according to the wavelength channel corresponding to the working OLT channel terminal. The adjustable protection OLT channel terminal then activates its transmitter and transmits a downlink signal, confirming that the optical network unit corresponding to the working OLT channel terminal has received the downlink signal and establishing a connection. Through this method, a one-to-many channel terminal protection switching mechanism is implemented using the adjustable protection OLT channel terminal and based on the ICTP activation message, solving the problem that the original protection method could not achieve one-to-many protection for OLTCs. This improves the versatility of the protection mechanism, reduces the overall complexity of the protection switching mechanism, and effectively reduces the overall cost of the WDM-PON system using this protection.

[0062] In an exemplary embodiment, the method further includes: when the adjustable protection optical line terminal channel terminal enters the initial state, it starts a timer; if the timer expires, the adjustable protection optical line terminal channel terminal enters the protection state.

[0063] In this embodiment, a timer is set in the adjustable protection optical line terminal (APC) as an alternative state transition method. After power-on, the APC enters an initial state. In the initial state, the APC does not perform a handshake mechanism and starts the timer. If the timer expires, the APC enters the protection state as a backup. Unlike traditional state transition methods, in this embodiment, only the APC can enter the protection state, while the active optical line terminal (OLT) will not.

[0064] Optionally, the state transition procedure for the adjustable protection optical line terminal channel terminal is as follows: In the initial state, a timer is started; if an activation message is received, it enters the pre-protection state. In the initial state, if the timer expires, it enters the protection state.

[0065] Optionally, the state transition procedure for the adjustable protection optical line terminal channel terminal is as follows: In the initial state, a timer is started; if the timer expires, the terminal enters the protection state. In the protection state, if an activation message is received, the terminal enters the pre-protection state.

[0066] In this embodiment, the adjustable protection optical line terminal channel terminal sets a timer, and the transition process from the initial state to the protection state is completed based on the timer, which provides a basis for activating the adjustable protection optical line terminal channel terminal and ensures the feasibility of the one-to-many channel terminal protection switching mechanism.

[0067] In an exemplary embodiment, after step 206, the method further includes: if the adjustable protection optical line terminal channel terminal in the pre-operating state receives an uplink transmission confirmation message, it enters the operating state; in the operating state, if the adjustable protection optical line terminal channel terminal receives an upper-level management event from the element management system, it enters a help-seeking state; in the help-seeking state, the adjustable protection optical line terminal channel terminal sends a channel terminal inter-terminal protocol activation message to the operating optical line terminal channel terminal in the initial state, in an attempt to instruct the operating optical line terminal channel terminal to migrate from the initial state to the pre-operating state.

[0068] In this system, the adjustable protection optical line terminal (OPCLT) attempts to establish a connection with the optical network unit corresponding to the working OPCLT by sending downlink signals. If an uplink transmission confirmation message is received, it indicates that the connection has been successfully established, and the OPCLT enters the working state. Through upper-level management events of the Element Management System (EMS) (e.g., EMS:Forced()), the working OPCLT can be instructed to relinquish its active role and transfer control of the corresponding wavelength channel to the original working OPCLT, i.e., the working OPCLT in its initial state. Specifically, in response to this upper-level management event, the OPCLT enters a distress state and sends an inter-terminal protocol activation message (e.g., ICTP:Active() message) to the working OPCLT in its initial state. It is understood that after the protected object's fault is cleared and it re-enters the initial state, this embodiment, through upper-level management events, promptly instructs the working OPCLT to send an inter-terminal protocol activation message to the protected object, causing the protected object to switch back to its working role.

[0069] In response to the activation message, the working optical line terminal (OLT) channel terminal continues the subsequent state transition, gradually moving from the initial state to the pre-working state and then to the working state. Specifically, in the initial state, if the working OLT channel terminal receives an inter-channel terminal protocol activation message, it enters the pre-working state, transmits downlink signals, and attempts to establish a connection with the optical network unit (ONU); if it receives an uplink transmission acknowledgment message, it enters the working state. In this way, the working OLT channel terminal resumes normal operation and achieves the switching of its working role.

[0070] Optionally, upper-level management events can be manually input into the element management system, or they can be automatically generated by the element management system after detecting that the working optical line terminal channel terminal has returned to its initial state. This embodiment does not impose any limitations on this.

[0071] In this embodiment, after the working optical line terminal channel terminal returns to its initial state, the adjustable protection optical line terminal channel terminal transfers control of the wavelength channel back to the working optical line terminal channel terminal, ensuring that the wavelength division multiplexing passive optical network system returns to normal operation.

[0072] In an exemplary embodiment, after sending an inter-channel terminal protocol activation message to a working optical line terminal in its initial state, the method further includes: the adjustable protection optical line terminal responding to a fault description event and returning to the protection state.

[0073] The fault description event can be generated by the working optical line terminal channel terminal or by the adjustable protection optical line terminal channel terminal. It is used to indicate that the transmission link is fault-free or that the fault cannot be determined to be caused by the transmission link. In response to the fault description event, the adjustable protection optical line terminal channel terminal returns to the protection state as a backup, so that the steps of the aforementioned optical line terminal channel terminal protection method can be re-executed when triggered by an activation message sent by any working optical line terminal channel terminal.

[0074] In this embodiment, the adjustable protection optical line terminal channel terminal switches back to the protection state, providing a reliable backup option for the wavelength division multiplexing passive optical network system. When any working optical line terminal channel terminal has a problem, the backup role can be quickly activated, thereby maintaining the stability of the wavelength division multiplexing passive optical network system.

[0075] Understandably, referring to Figure 5 , Figure 5 This is a schematic diagram of a Class B protection state machine for a conventional PON system in one embodiment; the conventional OLT CT Class B protection method can be summarized as follows:

[0076] 1. Upon entering the initial state (O1), an OLT CT first performs an ICTP handshake with its Class B protected counterpart OLT CT to confirm its effective role in protection allocation (including active role and backup role). When an OLT CT (let's say CT-A) receives an uplink transmission message, it indicates that another OLT CT is active on that channel pair. CT-A enters the pre-protection state (O2) and continues the handshake. Once CT-A is declared as a backup role via a specific ICTP message, it will directly enter the protection state (O3).

[0077] 2. CT-A in protected state continuously monitors the uplink signals of its channel pair. If no uplink burst is received within a certain time, CT-A enters LOS-P state (O4) and queries the Class B protected OLT CT (assuming it's CT-B) for potential protection role switching. If CT-B resumes transmission, CT-A returns to protected state; if CT-A is declared as active via a specific ICTP message, it enters pre-working state (O5) and attempts to establish a connection with the subordinate ONU of the channel pair by sending downlink transmissions. Once an uplink transmission confirmation is received, CT-A enters working state (O6).

[0078] 3. If a CT-A in working condition does not receive an uplink transmission within a certain period of time and declares a sudden loss of its subordinate ONU, it will enter the LOS-W state (O7, i.e., working signal loss state) and continue to attempt downlink transmission. If it still does not receive an uplink burst response within a certain period of time, the CT-A will enter the distress state (O8) and request protection switching from the CT-B via an ICTP message.

[0079] 4. Additionally, when CT-A does not receive an uplink signal in response to its downlink transmission, or does not receive an acknowledgment message from CT-B, it will enter a normal error state (O9), which may indicate a fiber optic or optical transceiver failure. When CT-A detects a failure in a major local device that requires immediate protection switching, it will enter a device error state (O10). CT-A in the above error states will be reinitialized via network management control after the error is cleared; while CT-A in a normal error state can directly enter a pre-protection state if it receives an uplink burst after the fault is cleared.

[0080] It should be noted that in the traditional OLT CT Class B protection method, the working OLT CT and the protection OLT CT corresponding to the same wavelength channel provide one-to-one protection in the protection process. Each OLT CT switches between protection and working states by monitoring the uplink transmission. To achieve one-to-many protection, a wavelength-tunable OLT CT is required. However, due to the characteristics of WDM-PON, channels transmit based on different wavelength channels and are isolated from each other. The OLT CT cannot directly perform global monitoring of the uplink signals of all wavelength channel pairs. Therefore, the traditional protection mechanism is not compatible with wavelength-tunable OLT CTs. Based on this, the embodiments of this application simplify and improve the original protection process to achieve the usability of the mechanism using wavelength-tunable OLT CTs.

[0081] In one alternative implementation, refer to Figure 6 , Figure 6 This is a schematic diagram of an improved Class B protection state machine in one embodiment; the optical line terminal channel terminal protection method provided in this application includes the following steps:

[0082] 1. With the OLT CT operating normally, connect the wavelength-adjustable protection OLT CT and activate it. After the wavelength-adjustable protection OLT CT is powered on, the protection OLT CT will enter the initial state (O1).

[0083] 2. In the initial state, the protection OLT CT does not perform a handshake mechanism, starts the first timer (hereinafter referred to as the Tpstart timer), and stays in the initial state for a period of time.

[0084] 3. During the Tpstart timeout period, the working OLT CT continues to operate normally until the Tpstart timer expires. If the Tpstart timer expires, the protection OLT CT will enter the protection state (O3) as a backup. In this state machine, only the protection OLT CT will enter the protection state. It can be understood that in the protection state, the protection OLT CT is protecting multiple working OLT CTs and can obtain the service information of the working OLT CTs.

[0085] 4. When a working OLT CT experiences a QLOS event, it enters the LOS-W state (O7, i.e., signal loss state) and continues to transmit downlink signals. After a period of time, if the working OLT CT in the O7 state still does not receive the corresponding uplink signal, it sends an Inter-Channel Protocol Activation (ICTP) message, i.e., ICTP:Active(), to the protection OLT CT.

[0086] 5. If the protection OLT CT in the initial state receives the ICTP:Active() message, the protection OLT CT will enter the pre-working state (O5) as the active role, and immediately tune its transmit and receive wavelengths according to the wavelength channel pair of the OLT CT that sent the ICTP message, and attempt to connect with the ONU under that channel pair.

[0087] 6. If the protected OLT CT in the protection state receives the ICTP:Active() message, it will enter the pre-operation state (O5), and tune its transmit and receive wavelengths according to the wavelength channel pair of the OLT CT that sent the ICTP message, and attempt to connect with the ONU under that channel pair.

[0088] 7. After receiving the uplink transmission confirmation, the protection OLT CT will operate normally in the working state.

[0089] 8. When the original working OLT CT is cleared of fault and re-enters the initial state (O1), the upper-level management event EMS:Forced() of the element management system instructs the protection OLT CT in working state (O6) to relinquish its active role and transfer control of the wavelength channel pair to the original working OLT CT. At the same time, the protection OLT CT enters the help state (O8) and sends the ICTP:Active() message to the original working OLT CT in the initial state (O1).

[0090] 9. In the distress state, the adjustable protection OLT CT indicates through specific events that the transmission link is fault-free or that the fault cannot be temporarily determined to be caused by the transmission link, and then returns to the protection state from the backup role. The original working OLT CT will continue subsequent state transitions until it returns to normal working state.

[0091] It should be noted that, referring to Figure 6 Compared with the traditional OLT CT Class B protection method, the optical line terminal channel terminal protection method provided in this application has the following characteristics:

[0092] 1. In the initial state, the protection OLT CT starts the Tpstart timer. If the ICTP:Active() message is received within the Tpstart time, it will transition to the pre-working state to attempt pre-working; or, if Tpstart times out, it will transition to the protection state as a backup.

[0093] 2. In the protection state, the protected OLT CT is in a protection state for multiple working OLT CTs and can obtain service information from the Active OLT CT. Upon receiving the ICTP:Active() message, it will transition to the pre-operation state, simultaneously tuning its transceiver to the corresponding wavelength channel and attempting to connect with its subordinate ONU.

[0094] 3. A single wavelength-tunable protection OLT CT protects multiple working OLT CTs via ICTP message interaction, without using traditional uplink signal monitoring for state transitions. Therefore, the pre-protection state (O2) and LOS-P state (O4) in the original state machine are not applicable in systems using wavelength-tunable protection OLT CTs. This embodiment simplifies these states and processes. For example, refer to Table 1, which illustrates a state transition method for protecting an OLT CT.

[0095] Table 1:

[0096]

[0097] Reference Figure 6For example, after entering the distress state, the adjustable protection optical line terminal channel terminal starts a third timer (hereinafter referred to as the Tictp timer). If the Tictp timer expires, the adjustable protection optical line terminal channel terminal returns to the protection state. For example, after entering the initial state, the adjustable protection optical line terminal channel terminal starts a second timer (hereinafter referred to as the Tsstart timer). If the Tsstart timer expires, the adjustable protection optical line terminal channel terminal enters the pre-operation state. For example, when the adjustable protection optical line terminal channel terminal is in the operating state, if a signal loss event (QLOS event) occurs, the adjustable protection optical line terminal channel terminal enters the LOS-W state (operating signal loss state), continuously transmitting downlink signals and continuously listening for uplink signals. When the adjustable protection optical line terminal (OPCLT) is in LOS-W state, it starts the fourth timer (hereinafter referred to as the Thold timer) and the fifth timer (hereinafter referred to as the Twfail timer). If an uplink signal is detected within the timer period, indicating that the signal loss event has been cleared (i.e., LOS cleared), the OPCLT returns to the working state. If the Thold and Twfail timers expire, the OPCLT enters the emergency state. For example, if the OPCLT in the emergency state receives an ICTP:Standby-Clear() message, it enters the normal error state; if it receives an ICTP:Standby-LOS() message, it enters the protection state. It is understood that... Figure 6 The transition process between normal error states and device error states is not shown in the figure. For details, please refer to the traditional OLT CT Class B protection method. This embodiment does not limit it.

[0098] In one exemplary embodiment, such as Figure 7 As shown, the optical line terminal channel terminal protection method also includes:

[0099] Step 702: If the working optical line terminal channel terminal in the working signal loss state still does not receive an uplink signal within a set time period, it enters the help state and periodically sends an inter-channel terminal protocol activation message to the adjustable protection optical line terminal channel terminal.

[0100] In the normal operation of the wavelength division multiplexing passive optical network system, each working optical line terminal (OLT) channel terminal is in an active state. If any working OLT channel terminal experiences a signal loss event (QLOS event), it enters a LOS-W state (signal loss state), continuously transmitting downlink signals and continuously monitoring the uplink signals of its own wavelength channel. If no uplink signal is received within a set time period, the working OLT channel terminal in the LOS-W state sends an activation message to the adjustable protection OLT channel terminal via the ICTP interface. The set time period can be adjusted according to actual conditions; this embodiment does not limit the specific value.

[0101] In one optional implementation, if a working optical line terminal (OLT) channel terminal in the LOS-W state does not receive an uplink signal within a set time period, the working OLT channel terminal enters a distress state. In the distress state, the working OLT channel terminal sends an inter-channel terminal protocol activation message to the adjustable protection OLT channel terminal.

[0102] Upon receiving the activation message, the adjustable protection optical line terminal (APLT) determines whether it is in the initial state or the protection state. If so, it proceeds with the subsequent state transition. For details, please refer to the explanations of steps 402 to 404 above, which will not be repeated here. If the adjustable protection APLT has already taken over the role of another working APLT, the working APLT in the distress state will not receive a response and will continue to remain in the distress state, periodically sending activation messages at a certain frequency until it receives a response from the adjustable protection APLT.

[0103] In this embodiment, a one-to-many channel terminal protection switching mechanism based on ICTP activation messages is implemented by a wavelength-tunable protection optical line terminal channel terminal, which solves the problem that the original protection method cannot achieve one-to-many protection of OLT CT, improves the versatility of the protection mechanism, reduces the complexity of the overall protection switching mechanism, and effectively reduces the overall cost of the WDM-PON system with application protection.

[0104] In an exemplary embodiment, after periodically sending an inter-channel terminal protocol activation message to the adjustable protection optical line terminal channel terminal, the method further includes: the working optical line terminal channel terminal entering a normal error state; if the working optical line terminal channel terminal in the normal error state receives reset information from the element management system, it migrates to the initial state.

[0105] In this configuration, after the working optical line terminal (OLT) transfers control of the wavelength channel to the adjustable protection OLT, it enters a normal error state, indicating a possible fiber optic or transceiver failure. Optionally, if it receives a response from the adjustable protection OLT, the working OLT enters a normal error state.

[0106] The reset information indicates that the fault of the working optical line terminal (OLT) channel terminal has been cleared. In response to this reset information, the OLT channel terminal transitions from a normal error state to an initial state. Specifically, after the fault of the OLT channel terminal is cleared, the state of the OLT channel terminal is reinitialized through the element management system. The OLT channel terminal receives the reset information sent by the element management system and, based on this reset information, transitions from a normal error state to an initial state.

[0107] In this embodiment, a recovery method for the working optical line terminal channel terminal is provided. After the fault is cleared, the working optical line terminal channel terminal is restored to its initial state, which facilitates the subsequent takeover of control of the wavelength channel from the adjustable protection optical line terminal channel terminal.

[0108] In an exemplary embodiment, the method further includes: if the working optical line terminal channel terminal in the initial state receives an inter-channel terminal protocol activation message sent by the adjustable protection optical line terminal channel terminal, it migrates to the pre-working state.

[0109] In this system, when the adjustable protection optical line terminal (OLT) channel terminal receives an upper-level management event from the element management system while in operation, it enters a distress state. In this distress state, it sends an inter-channel terminal protocol activation message to the operating OLT channel terminal in its initial state. The operating OLT channel terminal responds to this activation message and continues the subsequent state transition, gradually moving from the initial state to the pre-operating state and then to the operating state. Specifically, if the operating OLT channel terminal receives the activation message in its initial state, it enters the pre-operating state, sends a downlink signal, and attempts to establish a connection with the optical network unit; if it receives an uplink transmission confirmation message, it enters the operating state. In this way, the operating OLT channel terminal resumes normal operation and achieves a switchover of its operational role.

[0110] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0111] Based on the same inventive concept, this application also provides a wavelength division multiplexing passive optical network system for implementing the optical line terminal channel termination protection method described above. The solution provided by this system is similar to the implementation scheme described in the above method; therefore, the specific limitations in one or more wavelength division multiplexing passive optical network system embodiments provided below can be found in the limitations of the optical line terminal channel termination protection method described above, and will not be repeated here.

[0112] In one exemplary embodiment, reference is made to the foregoing Figure 1 This application provides a wavelength division multiplexing passive optical network system, the system including an adjustable protection optical line terminal (OLT) channel terminal and multiple working OLT channel terminals, wherein the adjustable protection OLT channel terminal and the working OLT channel terminals are connected via an inter-channel terminal protocol communication connection; wherein:

[0113] The adjustable protection optical line terminal channel terminal is used to perform the following steps:

[0114] When in the initial state or protection state, if a channel terminal protocol activation message is received from any working optical line terminal channel terminal, it enters the pre-working state.

[0115] In the pre-operation state, the operating wavelength of the transceiver is tuned according to the wavelength channel corresponding to the working optical line terminal channel terminal.

[0116] Turn on the transmitter and transmit the downlink signal, confirm that the optical network unit corresponding to the working optical line terminal channel terminal has received the downlink signal, and establish a connection;

[0117] The working optical line terminal (OLT) channel terminal is used to perform the following steps:

[0118] If no uplink signal is received within a set time period when the working signal is lost, the system enters a distress state and periodically sends an inter-channel terminal protocol activation message to the adjustable protection optical line terminal.

[0119] In an exemplary embodiment, the adjustable protection optical line terminal channel terminal is further configured to: start a timer when entering the initial state; and enter the protection state if the timer expires.

[0120] In an exemplary embodiment, the adjustable protection optical line terminal channel terminal is further configured to: enter the working state if an uplink transmission confirmation message is received in the pre-working state; enter the distress state if an upper-level management event from the element management system is received in the working state; and send an inter-channel terminal protocol activation message to the working optical line terminal channel terminal in the initial state in the distress state, in an attempt to instruct the working optical line terminal channel terminal to migrate from the initial state to the pre-working state.

[0121] In one exemplary embodiment, the adjustable protection optical line terminal channel terminal is further configured to: respond to a fault description event and return to the protection state.

[0122] In an exemplary embodiment, the working optical line terminal channel terminal is also used to enter an error state; in a normal error state, if a reset message from the element management system is received, it migrates to the initial state.

[0123] In an exemplary embodiment, the working optical line terminal channel terminal is further configured to, in the initial state, migrate to the pre-working state if it receives an inter-channel terminal protocol activation message sent by the adjustable protection optical line terminal channel terminal.

[0124] In one exemplary embodiment, a communication device is provided, which may be a server, and its internal structure diagram may be as follows. Figure 8 As shown, the communication device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a method for protecting optical line terminal (OLT) channels.

[0125] Those skilled in the art will understand that Figure 8 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the communication device to which the present application is applied. Specific communication devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0126] In an exemplary embodiment, a communication device is provided, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to perform the following steps: when in an initial state or a protection state, if a channel terminal protocol activation message is received from any working optical line terminal (OLT) channel terminal, the device enters a pre-working state; in the pre-working state, the device tunes the operating wavelength of its transceiver according to the wavelength channel corresponding to the working OLT channel terminal; the device turns on the transmitter and transmits a downlink signal, confirms that the optical network unit corresponding to the working OLT channel terminal has received the downlink signal, and establishes a connection.

[0127] In one embodiment, when the processor executes the computer program, it further performs the following steps: upon entering an initial state, starting a timer; if the timer times out, entering a protection state.

[0128] In one embodiment, when the processor executes the computer program, it further implements the following steps: in the pre-working state, if an uplink transmission confirmation message is received, it enters the working state; in the working state, if an upper-level management event of the element management system is received, it enters the help-seeking state; in the help-seeking state, it sends a channel terminal protocol activation message to the working optical line terminal channel terminal in the initial state, in order to attempt to instruct the working optical line terminal channel terminal to migrate from the initial state to the pre-working state.

[0129] In one embodiment, when the processor executes the computer program, it also performs the following steps: responding to a fault description event and returning to a protected state.

[0130] In one embodiment, when the processor executes the computer program, it further implements the following steps: in the state of loss of working signal, if no uplink signal is received within a set time period, it enters the help state and periodically sends an inter-channel terminal protocol activation message to the adjustable protection optical line terminal channel terminal.

[0131] In one embodiment, when the processor executes the computer program, it further performs the following steps: entering an error state; and, if a reset message from the element management system is received in the normal error state, transitioning to the initial state.

[0132] In one embodiment, when the processor executes the computer program, it further performs the following steps: in the initial state, if a channel terminal protocol activation message is received from the adjustable protection optical line terminal channel terminal, the processor transitions to the pre-operation state.

[0133] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, it performs the following steps: when in an initial state or a protected state, if an inter-channel terminal protocol activation message is received from any working optical line terminal (OLT) channel terminal, it enters a pre-working state; in the pre-working state, it tunes the operating wavelength of its transceiver according to the wavelength channel corresponding to the working OLT channel terminal; it turns on the transmitter and transmits a downlink signal, confirms that the optical network unit corresponding to the working OLT channel terminal has received the downlink signal, and establishes a connection.

[0134] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: upon entering the initial state, a timer is started; if the timer times out, a protection state is entered.

[0135] In one embodiment, when the computer program is executed by the processor, it further implements the following steps: in the pre-working state, if an uplink transmission confirmation message is received, it enters the working state; in the working state, if an upper-level management event of the element management system is received, it enters the help-seeking state; in the help-seeking state, it sends a channel terminal protocol activation message to the working optical line terminal channel terminal in the initial state, in order to attempt to instruct the working optical line terminal channel terminal to migrate from the initial state to the pre-working state.

[0136] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: responding to a fault description event and returning to a protected state.

[0137] In one embodiment, when the computer program is executed by the processor, it further implements the following steps: In the state of loss of working signal, if no uplink signal is received within a set time period, it enters a distress state and periodically sends an inter-channel terminal protocol activation message to the adjustable protection optical line terminal channel terminal; after receiving the inter-channel terminal protocol activation message, the adjustable protection optical line terminal channel terminal enters a pre-working state, tunes its transceiver's working wavelength to the wavelength channel corresponding to the working optical line terminal channel terminal, turns on the transmitter and transmits a downlink signal, confirms that the optical network unit corresponding to the working optical line terminal channel terminal has received the downlink signal, and establishes a connection.

[0138] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: entering an error state; and, if a reset message from the element management system is received in the normal error state, migrating to the initial state.

[0139] In one embodiment, when the computer program is executed by the processor, it further performs the following steps: in the initial state, if an inter-channel terminal protocol activation message is received from the adjustable protection optical line terminal channel terminal, it transitions to the pre-operation state.

[0140] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0141] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0142] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0143] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for protecting the channel terminal of an optical line terminal, characterized in that, The method is applied to a wavelength division multiplexing passive optical network system, the system including an adjustable protection optical line terminal (OLT) channel terminal and a working OLT channel terminal, the adjustable protection OLT channel terminal being used to protect the working OLT channel terminal within the same system, the method comprising: When the adjustable protection optical line terminal channel terminal enters the initial state, the timer is activated; If the timer expires, the adjustable protection optical line terminal channel terminal will enter the protection state. When the adjustable protection optical line terminal channel terminal is in the protection state, if it receives a channel terminal inter-terminal protocol activation message sent by any working optical line terminal channel terminal, it will enter the pre-working state. In the pre-operation state, the adjustable protection optical line terminal channel terminal tunes the operating wavelength of its transceiver according to the wavelength channel corresponding to the working optical line terminal channel terminal. The adjustable protection optical line terminal channel terminal turns on the transmitter and transmits a downlink signal, confirms that the optical network unit corresponding to the working optical line terminal channel terminal has received the downlink signal, and establishes a connection.

2. The method according to claim 1, characterized in that, After the connection is established, the method further includes: If the adjustable protection optical line terminal channel terminal in the pre-operation state receives an uplink transmission confirmation message, it enters the working state. In the aforementioned working state, if the adjustable protection optical line terminal channel terminal receives an upper-level management event from the element management system, it enters a distress state. In the distress state, the adjustable protection optical line terminal channel terminal sends an inter-channel terminal protocol activation message to the working optical line terminal channel terminal in the initial state, in an attempt to instruct the working optical line terminal channel terminal to migrate from the initial state to the pre-working state.

3. The method according to claim 2, characterized in that, After sending the inter-channel terminal protocol activation message to the working optical line terminal (OLT) in its initial state, the method further includes: The adjustable protection optical line terminal channel terminal responds to the fault description event and returns to the protection status.

4. The method according to claim 1, characterized in that, The method further includes: If a working optical line terminal (OLT) channel terminal fails to receive an uplink signal within a set time period while in a signal loss state, it enters a distress state and periodically sends an inter-channel terminal protocol activation message to the adjustable protection OLT channel terminal.

5. The method according to claim 4, characterized in that, After periodically sending the inter-channel terminal protocol activation message to the adjustable protection optical line terminal, the method further includes: The working optical line terminal (OLT) channel terminal has entered a normal error state. Normally, if a working optical line terminal (OLT) in an error state receives a reset message from the element management system, it will migrate back to the initial state.

6. The method according to claim 5, characterized in that, The method further includes: If the working optical line terminal (OLT) in the initial state receives an inter-channel terminal protocol activation message sent by the adjustable protection OLT, it will transition to the pre-working state.

7. A wavelength division multiplexing passive optical network system, characterized in that, The system includes an adjustable protection optical line terminal (OLT) channel terminal and a working OLT channel terminal, wherein the adjustable protection OLT channel terminal and the working OLT channel terminal are connected via an inter-channel terminal protocol communication connection; wherein: The adjustable protection optical line terminal channel terminal is used to perform the steps of the method as described in any one of claims 1 to 3; The working optical line terminal channel terminal is used to perform the steps of the method as described in any one of claims 4 to 6.

8. A communication device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

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